Difference between revisions of "BGRABitmap tutorial TAChart"
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{{BGRABitmap tutorial TAChart}} | {{BGRABitmap tutorial TAChart}} | ||
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You can make beautiful charts using BGRABitmap. | You can make beautiful charts using BGRABitmap. | ||
Revision as of 21:35, 3 February 2013
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You can make beautiful charts using BGRABitmap.
BGRA rendering
First add the TAChartBGRA package. To render your chart, you can for example use a PaintBox. In the OnPaint event, write :
uses BGRABitmap, TADrawerBGRA;
procedure TForm1.PaintBox1Paint(Sender: TObject);
var
bmp: TBGRABitmap;
id: IChartDrawer;
rp: TChartRenderingParams;
begin
bmp := TBGRABitmap.Create(PaintBox1.Width, PaintBox1.Height);
Chart1.DisableRedrawing;
try
id := TBGRABitmapDrawer.Create(bmp);
id.DoGetFontOrientation := @CanvasGetFontOrientationFunc;
rp := Chart1.RenderingParams;
Chart1.Draw(id, Rect(0, 0, PaintBox1.Width, PaintBox1.Height));
Chart1.RenderingParams := rp;
bmp.Draw(PaintBox1.Canvas, 0, 0);
finally
Chart1.EnableRedrawing;
bmp.Free;
end;
end;
To avoid flickering, consider using TBGRAVirtualScreen from BGRAControls.
Text effects
To add text effect, you need the latest version of BGRABitmap, and the latest SVN of Lazarus. There is a FontRenderer property in each TBGRABitmap image, that you can define. You must not free the renderer, as it is automatically freed by the image.
The text effects are provided by the BGRATextFX unit that contains the TBGRATextEffectFontRenderer class. To add a golden contour to the letters and a shadow, add the following lines :
uses BGRATextFX, BGRAGradientScanner;
...
var
...
fontRenderer: TBGRATextEffectFontRenderer;
gold: TBGRAGradientScanner;
begin
...
fontRenderer:= TBGRATextEffectFontRenderer.Create;
fontRenderer.ShadowVisible := true; //adds a shadow
fontRenderer.OutlineVisible := true; //show the outline
gold := TBGRAGradientScanner.Create(CSSGold,CSSGoldenrod,gtLinear,PointF(0,0),PointF(20,20),true,true);
fontRenderer.OutlineTexture := gold; //define the texture used for the outline
fontRenderer.OuterOutlineOnly := true; //just the outer pixels of the text
bmp.FontRenderer := fontRenderer; //gives the FontRenderer to the image (which becomes the owner of the renderer)
...
gold.Free;
end;